Active-sterile neutrino oscillations at INO-ICAL over a wide mass-squared range

Abstract

We perform a detailed analysis for the prospects of detecting active-sterile oscillations involving a light sterile neutrino, over a large $\Delta m_{41}^2$ range of $10^{-5}$ eV${}^2$ to $10^2$ eV${}^2$, using 10 years of atmospheric neutrino data expected from the proposed 50 kt magnetized ICAL detector at the INO. This detector can observe the atmospheric ${\nu }_{\mu }$ and ${\bar{\nu }}_{\mu }$ separately over a wide range of energies and baselines, making it sensitive to the magnitude and sign of $\Delta m_{41}^2$ over a large range. If there is no light sterile neutrino, ICAL can place competitive upper limit on $|U_{\mu 4}{|}^2\lesssim 0.02$ at 90\% C.L. for $\Delta m_{41}^2$ in the range $(0.5-5)\times 10^{-3}$ eV${}^2$. For the same $|\Delta m_{41}^2|$ range, ICAL would be able to determine its sign, exploiting the Earth's matter effect in ${\mu }^{-}$ and ${\mu }^{+}$ events separately if there is indeed a light sterile neutrino in Nature. This would help identify the neutrino mass ordering in the four-neutrino mixing scenario.

Comments: 34 pages, 11 figures, 3 tables. Comments are welcome. Published in JHEP